Abstract: A folder comprising a sheet (1) which is pleated in a concertina-like fashion (10, 11, 12) and which, in a pleated state, is folded around fold lines (14, 15) that extend perpendicularly to the pleat line (10, 11, 12) in the pleated sheet, wherein the sheet (1) is surrounded by a protective cover (2) when in a fully folded-up state. The two sheet fold-lines (14, 15) extending perpendicular to the pleat lines (10, 11, 12) face in mutually the same direction, so as to enable the two end-panels of the pleated sheet (1) to be folded in overlapping relationship with the center panel. The cover (2) is a paperboard cover against which one pleated panel (40) of the sheet is fastened in a centered position on one side of the cover (2), wherein the cover also includes fold lines (24, 25) which coincide generally with the fold lines (14, 15) on the sheet (1).